Storage batteries (also called ‘rechargeable batteries’) as secondary cells are widely used in a variety of industrial fields requiring power sources such as batteries for vehicles, batteries for ships, UPS batteries, etc.
The storage batteries repeatedly performs a charge function of converting electric energy into chemical energy and a discharge function of converting chemical energy into electric energy using electrochemical reactions that are electrically reversible. If such rechargeable batteries are used for a long period of time, the performance thereof is deteriorated, thus undergoing a discarding process.